NICMOS, the Near-Infrared Camera and Multi-Object Spectrometer, is a
near-infrared (0.8 to 2.5 micron) imager and low resolution (R~200) spectrometer
scheduled for installation in the Hubble Space Telescope in February,
1997. Operating from orbit, NICMOS avoids the atmospheric effects (wavefront
distortion, OH emission, and absorption) which limit the capabilities of
ground-based instruments. Thus, NICMOS provides very stable, diffraction-limited
resolution (~0.1 arcsec) with high dynamic range (exceeding several million
using non-destructive reads). These capabilities enable the detection of
low-luminosity brown dwarfs as close companions to nearby stars. Coronagraphic
optics will suppress the direct and diffracted light from the primary star and
enable companions to be detected outside of a 0.3 arcsec radius. The Science
Team will conduct coronagraphic surveys of both nearby M dwarfs and young stars
to spot orbiting brown dwarfs with masses as low as ~5 Jupiters. We discuss the
observation strategies and capabilities of this technique. We will also search
for brown dwarfs as isolated field objects by conducting a grism (1 to 2 micron)
spectroscopic survey using NICMOS in a parallel mode of observation. This
spectral region contains important diagnostic features of brown dwarfs, such
as methane absorption. The sensitivity of NICMOS in this grism mode enables
brown dwarfs like Gl 229B to be detected ten times farther away, and greatly
exceeds the capabilities of any planned ground-based program. This survey
should also detect and characterize many objects in the poorly understood
transitional region between red- and brown dwarfs.
